Recently, as the tendency toward miniaturization, high functionalization, and large capacity of electronic equipment has been expanding and the need for densification and high integration of the semiconductor package has rapidly increased, the size of semiconductor chips has been becoming larger and larger. In terms of improvement of integration degree, the stack package method for stacking chips in multiple stages has gradually increased.
As for the stack packaging methods, a wire bonding method in which a wire of a metal such as gold or aluminum interconnects an electrode portion of a semiconductor pellet and a conductor layer disposed on a lead frame layer or stem, and a flip chip method that attaches a semiconductor chip by directly fusing an electrode pattern on its lower surface to a circuit board rather than using an additional link structure such as a metal lead (wire) or a separate medium such as a ball grid array (BGA), are known.
Meanwhile, in order to increase the ease of signal transmission of the semiconductor device and to control the operation of the semiconductor elements, a control semiconductor device (controller) is provided. However, the control semiconductor device, when fixed improperly, will lower the signal transmission efficiency or the transmission speed of the semiconductor package, destabilize the structure of the semiconductor device in the course of multistage stack packaging, and/or reduce the manufacturing yield and reliability of the semiconductor device.
Further, in order to protect integrated circuits (ICs) and similar devices, resin packaging is often carried out using various resins, mainly epoxy resin. Following the recent trend of miniaturization and weight reduction, the mainstream IC packaging method for packaging devices is called a surface mounting where ICs or other devices are mounted directly on a circuit board and liquid resin is utilized for packaging (under-fill process).
Such under-fill process attempts to solve the issue of thermomechanical fatigue. Specifically, the under-fill process includes filling a polymeric material that has excellent adhesion such as epoxy resin with inorganic particles so as to have a value close to the thermal expansion coefficient of the solder, and then applying the preparation to fill the gap between the chip and the printed circuit board. Here, the applied polymer composite material filled with the inorganic particles is called an underfill.
Generally known underfill materials being in liquid form cause underfill with high flowability to protrude to undesired portions of the device, resulting in unnecessary contamination, product defects, and/or difficulty in mounting at a high density.
It is known to form a preventive barrier or dam around the device.